Current cardiac treatments employing the use of catheters are dependent upon complexity of the location to be treated, unless surgery is employed to access complex locations. The physician has had to choose between placing the catheter and treating a site in a place of greatest interest or areas which are anatomically accessible with catheters. Prior catheter placement has been generally restricted to areas which can be repeatedly accessed by the physician. One approach to expand the areas in which a catheter can be placed includes the use of steerable catheters. One type of steerable catheter offers maneuverability to specific, otherwise inaccessible sites by providing catheters shaped specifically to access a particular site. This type of catheter is limited as it cannot be used to reach locations requiring active articulation during placement.
Other types of steerable catheters provide catheters having deflecting tips, which include a pullwire attached to the distal tip portion of the catheter. During use of this type of catheter, the wire is pulled causing the tip to defect. Alternatively, the wire is restrained while the catheter is advanced, allowing the distal tip to deflect. However, one drawback is that the tip of the catheter is deflected only in a prescribed manner. While the tip can be altered during the placement of the catheter, the steerable tip has a radius of curvature which is fixed, thus restricting the accessibility of the distal tip to certain anatomical sites. This results in a limit to the complexity of the site in which the catheter can be positioned.
Another drawback is that an inventory of different sized catheters is necessary, where each catheter has a differently sized radius of curvature. In addition, it is occasionally not known what size of radius is appropriate prior to the procedure. When it is discovered, after the catheter has been positioned, that the radius of the catheter is incorrect, the catheter must be completely withdrawn from the patient, and a new properly radiused catheter tip must be reintroduced into the heart. This substitution can cause additional trauma to the patient, and is costly since it adds time to the procedure. In addition, the initially selected but improperly sized catheter must then be discarded, never having been used for its intended purpose. This adds more unnecessary cost since the catheters are typically single use items which are discarded after a single use.
Accordingly, what is needed is a catheter which is adjustable, and which can be positioned within complex locations of a body and is able to accommodate a variety of anatomical variations. What is further needed is a catheter having a shape which is modifiable during a procedure.